Piezoelectric Nanogenerators for Self-powered Nanodevices

This chapter reviews the fundamental principles and recent development of piezoelectric nanogenerators that convert mechanical energy into electricity at the nanometer scale. Theoretical prediction of the piezoelectric potential output from a single nanowire is discussed first. The semiconductor-piezoelectric coupling effect, enhanced mechanical property, and the nanoscale flexoelectric enhancement are important aspects that make nanowire advantageous for mechanical energy harvesting. Several representative approaches are presented for characterizing the piezoelectric potential on nanowires. The ultrasonic wave-driven nanogenerator and power fiber are reviewed as two important prototypes. The most recent strategies integrating nanowires at macroscopic scale for providing sufficient electric energy for small electronic devices are also summarized and discussed. Challenges and future research opportunities are suggested at the end of this chapter.